Add vendor prefix for background-clip (#7727)

app/javascript/styles/mastodon/tables.scss

@@ -195,6 +195,7 @@ a.table-action-link {
       font-weight: 700;
       background: linear-gradient(to right, orange , yellow, green, cyan, blue, violet,orange , yellow, green, cyan, blue, violet);
       background-size: 200% 100%;
+      -webkit-background-clip: text;
       background-clip: text;
       color: transparent;
       animation: Swag 2s linear 0s infinite;